Packaging web and process

ABSTRACT

A packaging web is disclosed. The web is an elongate, flattened plastic tube having face and back sides delineating the faces and backs of a set of side by side bags. The tube includes an elongated top section and spaced sets of side seals each extending transversely from the bottom to a location near the top section. The side seals of each set delineate sides of adjacent bags such that the sides and bottoms delineate the perimeters of a set of open top bags. The top section is essentially a bottom open tube for providing bag support when the web is fed into a bag loading machine. The web includes superposed, spaced lines of weakness in each of the face and back sides delineating tops of the bags. Each such spaced line of weakness extends substantially across an associated bag top and terminates in spaced relationship with an associate one of the spaced lines of weakness to leave solid sections in the face and back sides.

[0001] This invention relates to packaging and more particularly to anovel and improved web of side connected open bags and a process ofpackaging with such a web.

BACKGROUND OF THE INVENTION

[0002] U.S. Pat. No. 5,743,070, issued Apr. 28, 1995 to Hershey Lernerand Dana J. Liebhart under the title of PACKAGING MACHINE, MATERIAL ANDMETHOD, discloses a machine and process of packaging with side connectedbags. U.S. Pat. No. 5,944,424 of Aug. 31, 1999 is a patent issuing froma divisional application which claims the packaging web as disclosed inboth patents (the SP Patents).

[0003] With the machine of the SP Patents, webs of side connected bagsare used. Each web is an elongated, flattened, plastic tube whichincludes a top section which itself is essentially a tube. In use thetop section is fed over a mandrel and past a slitter which separates thetop section into two upstanding lips. The lips are grasped by uniquebelts that are fed along divergent paths of travel into parallel pathsthrough a load station. The unique belts are described more fully inU.S. Pat. No. 5,722,218 issued Mar. 3, 1998 to Hershey Lerner under thetitle PLASTIC TRANSPORT SYSTEM (herein “the Belt Patent”). Thedisclosures of the SP Patents and the Belt Patent are incorporated byreference.

[0004] Each web includes side connected bags which depend from the lips.As a web is fed along its path of travel through a machine of the SPPatent (the SP Machine), lines of weakness interconnecting sides ofadjacent bags are ruptured to leave individual bags depending from thelips.

[0005] As the belts diverge, the gripped lips are separated from thedepending bags along lines of weakness to the extent necessary to causethe bags to span the space between the parallel paths in a generallyrectangular opening.

[0006] As indicated in U.S. Pat. No. 6,035,611 issued Mar. 14, 2000 anddisclosing an improved process of making such a web, (the ProcessPatent) the system disclosed in the SP patents has, on occasion,experienced difficulty. More specifically, there is a tendency for bagsto fail to open in the intended rectangular shape because the separationof supporting lips from the front and back faces of the bags is notequal. This appears to be due, at least in part, to the manner in whicha pair of lines of continuous perforations are formed along the web. Toooften the webs are not perforated evenly in both the front and backwebs. This occurs because) toothed rotary knives used to form thecontinuous perforations, have pointed teeth. The teeth penetrate throughone web into the other in forming the perforations. Since the teeth arepointed, the length of each perforation in the first penetrated web isgreater than in the other.

[0007] While the process disclosed and claimed in the Process Patent hasdiminished the scope of the problem, there remains a problem in that alltoo often a lead portion of the bag will open to a greater extent than atrailing portion as the web is fed into and through a load station.

[0008] A somewhat similar system utilizes special guide tracks whichsupport a specialized web. In one embodiment, that specialized web hasupstanding lips, each of which has a section of an associated,continuous, enlarged top portion. The top portions are supports that arefed into the special guides that are in the form of tubes. The tubes areopen at the bottom so that the web hangs from the enlarged portions. Theweb has a series of side connected bags suspended from the continuoustop portions. Lead and trailing sections of each bag are slit anappropriate amount to permit the bag to open a desired amount andhopefully to a rectangular shape. Since neither the specialized guidesnor the web can be adjusted, there is a need for precision in themanufacture which, given manufacturing tolerances, is at best difficultto obtain. Moreover, as the bags are fed to a load station, they areonly supported in central portions and not throughout their longitudinallengths. Further, because of the special guide tracks, the cost ofmaking the guide tracks and a packaging web is greater than the cost ofmaking a web for the SP Machine. Moreover in use change over from onepackaging run to another is far simpler with the SP machine.

[0009] Accordingly, it would be desirable to refine the applicant'ssystem to provide a web in which bags reliably and consistently open torectangular shapes and in which bags are more positively supported thanthe prior webs of the somewhat similar system to enable packaging ofheavier objects. In addition it would be desirable to maintain the easeand speed of change over available with the web of the SP Patents fromone packaging operation to another for a different product.

SUMMARY OF THE INVENTION

[0010] The present invention is directed to a web of side connected bagswhich web is an improvement over the webs disclosed and claimed in theSP and Process Patents. The improved web provides the web feedadvantages over other prior art that are provided by the webs of the SPand Process Patents. In addition, the web of the present inventionassures rectangular opening of bags as they are transported through aload station and enhanced load support enabling the packaging of heavieritems than can be supported by the webs of the SP and Process Patents.

[0011] The improved web, like the predecessors, is an elongated flattentube having face and back sides delineating the faces and backs of a setof side by side bags. The tube includes an elongated top section whichis adapted to be slit to provide front and back web supporting lips.Spaced sets of side seals extend transversely upwardly from the bottomof the web to delineate sides of adjacent bags.

[0012] Unlike the webs of the SP and Process Patents, the tops of thebags each have a spaced pair of, rather than continous, lines ofweakness. The spaced pair of each bag extend from further lines ofweakness delineating the sides of the bags. The spaced pair of lines ofeach bag are each of length which is one-half the width of a desired bagopening when a bag is rectangularly configured as it passes through theload station. The solid web sections between the spaced lines ofweakness assure equal opening along the leading and trailing sides ofeach bag as it passes through the load station. The solid sections alsoprovide enhanced load support for a given material of like chemistry andthickness. Thus heavier products can be packaged and forces resultingfrom a product being loaded striking a bag are better absorbed.

[0013] The improved web of the present invention produces a number ofoutstanding and indeed unexpected advantages. These advantages occur inboth the equipment used to make the web and the equipment used inpackaging products. The costs of manufacture and of packaging are bothreduced because both the manufacturing and the packaging equipment canbe run at higher speeds. Further, the precision required of equipmentused to make the bags is reduced, contributing to a reduction in thecost of packaging.

[0014] The reduction in the cost of manufacturing and the higher onmanufacturing through put achieved occur because the manufacturingtolerances with respect to the side seals and the perforations are farless rigid. The cost of making manufacturing machines is reduced by theelimination of such things as edge guides. The looser tolerances areachieved because there is less loading on the side seals duringpackaging. Tolerances in the lines of weakness along the tops of the bagare loosened because the packaging process now relies on the solidcentral sections of the web to control the extent of separation of thetop lips from the bags as a web enters the packaging station.

[0015] In packaging operations higher through puts are achievablebecause the webs are better able to withstand forces that are occurringduring the packaging operation. In addition for many products wheresupport conveyors have been required in the past, the need for thosesupport conveyors is eliminated.

[0016] Accordingly the objects of the invention are to provide a noveland improved packaging web and a method of packaging.

BRIEF DESCRIPTION OF THE DRAWINGS

[0017]FIG. 1 is a perspective view showing the web of the SP Patentsbeing fed through a load station of the machine of the SP Patents; and,

[0018]FIG. 2 is an elevational view of the web of the present invention.

PREFERRED EMBODIMENT OF THE INVENTION

[0019] Referring to FIG. 1, a web 15 of side connected bags is provided.The web 15 is fed from a supply (not shown) to a load station 17.

[0020] The web 15 is an elongated flattened plastic tube, typicallyformed of polyethylene. The tube includes a top or lip section 23 forfeeding along a mandrel 24. The top section 23 is connected to the topsof a chain of side connected bags 25 by front and back longitudinallyextending lines of weakness in the form of perforations 27, 28.Frangible interconnections 30 connect adjacent bag side edges. Each bag25 includes a face 31 and a back 32 interconnected at a bottom 33 by aselected one of a fold or a seal when the bags are top loaded. When thebags are bottom loaded the bottom of the web will be the top of apackage when formed. In that event the web bottom may be a reuseableclosure such as those sold under the trademark Ziplock®.

[0021] Side seals 34 adjacent the interconnections 30 delineate thesides of the bags 25. The bag faces and backs 31, 32 are respectivelyconnected to the top section 23 by the lines of weakness 27, 28, suchthat the top section 23 itself is essentially a tube.

[0022] The web 15 is fed into a bag feed and preparation station 35. Thefeed is over the mandrel 24 and past a slitter 36, FIG. 1. The slitter36 separates the lip section 23 into opposed face and back lips. Thefeed through the bag feed and preparation portion 35 is caused by a pairof endless, oppositely rotating main transport belts 40, 41 supported byoppositely rotating pulley sets.

[0023] A plow 45 is provided and shown in FIG. 1. The plow is positioneda short distance upstream from a roller cam 46. As the lips are drawnalong by the main transport belts 41, 42 the lips are respectivelyfolded over the main transport belts under the action of the plow 45.

[0024] Once the lips are folded over the tops of the main transportbelts 41, 42, the roller cam 46 presses endless lip transport and clampbelts 48, 49 into complemental grooves in the main transport belts 41,42 respectively. Thus, the grooves function as bag clamping surfacesthat are complemental with the clamping belts 48, 49 as is describedmore fully in the Belt Patent.

[0025] A bag side separator mechanism 53 is provided at a bag connectionbreaking station. The separation mechanism shown is not currentlyproduced for SP Machines. Since it is an operative mechanism and themachine is disclosed for environment and to explain the problem overcomeby the present invention, we have not updated that aspect of the presentdisclosure.

[0026] The separator mechanism 53 includes an endless belt 54 which istrained around a pair of spaced pulleys 55 to provide spans which, asshown in FIG. 1, are vertical. The pulleys 55 are driven by a motor, notshown. As the belt is driven breaking pins 58 projecting from the belt54 pass between adjacent sides of bags to break the frangibleinterconnections 30. Thus, as the bags depart the bag feed andpreparation portion 35, they are separated from one another but remainconnected to the lips 38, 39.

[0027] The load station 17 includes a pair of parallel belts spreaders61, 62. The belt spreaders are mirror images of one another. The beltspreaders include spaced channels which respectively guide the maintransport belts 40, 41, on either side of the load station 17. When thetransport belts 40, 41 are in the channels, as is clearly seen in FIG.1, the bags 25 are stretched between the belts in a rectangular topopening configuration.

[0028] A schematic showing of a supply funnel 66 is included in FIG. 1.As suggested by that Figure, products to be packaged are depositedthrough the rectangular bag openings each time a bag is registered withthe supply funnel at the load station.

[0029] A space adjusting mechanism as described in the SP Patents, butnot shown, includes a spaced pair of adjustment screws. The adjustmentmechanism drives the spreaders equally and oppositely into an adjustedspacial, but still parallel, relationship.

[0030] As loaded bags exit the load station, it is desirable to returnupper portions of the bag faces and backs into juxtaposition. Tofacilitate this return the bag tops are stretched. This stretching ofthe now loaded bags as they exit the load station is accomplished withjets of air from nozzles 75, 76 which respectively direct air streamsagainst the lead and trailing edges of the bag being stretched. Thisstretching of the bags assists in moving them from their rectangularorientations into face to back juxtaposed relationships as the transportbelts are returned to juxtaposition.

[0031] The Improved Web

[0032] Referring now to FIG. 2, an improved web 15′ is shown. Theimproved web 15′ includes a top section 23′ and side seals 34′ each ofwhich is bisected by a frangible side connection or line of weakness30′. The top section 23′ supports a plurality of side connected bags25′. The web has a bottom 33′. On many occasions the web bottom 33′ isdelineated by what in fact will become the top of finish packages madefrom the bags 25′. Where each bag 25′ is a header bag or a bag whichincludes a reusable closure, product loading is through what will becomethe bottom of the bag.

[0033] Each bag 25′ includes a pair of spaced lines of weakness 80, 81which provide an outstanding feature of the present invention. Each ofthe spaced lines 80, 81 extends from an associated frangible sideconnection or line of weakness to delineating the edge of the bag. Thespaced lines of weakness extend toward one another from their respectiveand associated side lines of weakness terminating in spaced relationshipwith a solid section 84 of web therebetween in each of the face in theback of the web. Thus, while the web 15′ is shown in side elevation inFIG. 2, it will be recognized that is has a face and a back just as itspredecessor as shown in FIG. 1 and in the referenced SP and ProcessPatents.

[0034] Each of the spaced lines of weakness is of a length one-half thewidth to which that bag is to be opened when in the load station 17.Thus, aligned lines of weakness 80 in the face and a back, assuming theweb of FIG. 2 is fed to the left, will define the top of a lead side ofa bag passing through the load station 17 while the front and back lines81 will define the trailing side.

[0035] Registration indicia are shown at 86 in FIG. 2. These indicia arepreferably transparent and are made in accordance with the disclosure inU.S. Pat. No. 4,680,205 entitled Continuous Web Registration.

[0036] Operation

[0037] In operation a web 15′ will be fed from a supply not shown to theweb preparation station 35. There the top section 23′ is fed over themandrel 24 and split by the slitter 36 into opposed face and back websupporting lips. The lips are grasped by the belts 41, 42, 48, 49 andthen transported into the load station 17. As each bag 25′ enters theload station, the lips are separated from the bag along the lead linesof weakness 80. As the lead side of the bag enters into the load stationthe trailing side is separated this time along the trailing ones of thespaced lines of weakness 81.

[0038] As the web progresses through the load station each bag is firmlysupported by its solid sections 84 so that heavier items then could bepackaged with the bags of the SP and Process Patents can be supported.Moreover, the solid section 84 function to limit the extent of openingalong the spaced lines of weakness 80, 81.

[0039] In setting up the machine or in feeding a new web through themachine after a previous web has completed its passage fine adjustmentsof the belt spreaders 60, 61 can be made to assure appropriate spacingfor the web being fed and thus compensating for any variations due tosuch things a manufacturing variations within a tolerance range

[0040] Although the invention has been described in its preferred formwith a certain degree of particularity, it is understood that thepresent disclosure of the preferred form has been made only by way ofexample and that numerous changes in the details of construction,operation and the combination and arrangement of parts may be resortedto without departing from the spirit and the scope of the invention ashereinafter claimed.

What is claimed is:
 1. A packaging web comprising: a) an elongate,flattened plastic tube having face and back sides delineating the facesand backs of a set of side by side bag portions; b) the flattened tubeincluding bag bottom structure interconnecting the bag faces and backsand delineating bottoms of side by side bag portions; c) the bottomstructure being a selected one of a fold, a reusable fastener and aseal; d) the tube including an elongated top section; e) spaced sets ofside seals each extending transversely from the bottom structure to alocation near the top section, the side seals of each set delineatingsides of an adjacent pair of bags such that the sides and bottomsdelineate the perimeters of a set of open top bags; f) the top sectionbeing essentially a tube with a bottom opening, the top section beingfor providing bag support when the web is fed into a bag loadingmachine; g) the top section being adapted to be slit to form a pair ofstrips which function as web supporting lips, the slitting occurring asthe web is fed along a path of travel to form the supporting lips andthe bag portions are supported by the lips as the web is fed through abag loading station; h) the web including superposed, spaced lines ofweakness in each of the face and back sides delineating a top of each ofthe bags and demarcation lines between the bag faces and backs and thetop section; I) the web including further lines of weakness betweenadjacent bag sides to allow facile separation of adjacent bag sides;and, j) the spaced lines of weakness being generally normal to thefurther lines of weakness, each such spaced line of weakness extendingsubstantially from an associated further line of weakness across anassociated bag top and terminating in spaced relationship with anassociated one of the spaced lines of weakness across the top of saidassociated bag top whereby to leave solid sections in the face and backatop said associated bag, the solid sections serving to limit separationof said associated bag from the lips along said spaced lines of weaknessas the web is fed along the path of travel into and through the loadstation, thereby assuring rectangular bag opening and support for anitem to be packaged when placed in said associated bag.
 2. The web ofclaim 1 wherein the further lines of weakness are frangible connectionsbetween the side seals of adjacent bags.
 3. The web of claim 1 whereinthe further lines of weakness are each formed in an associated sideseal.
 4. The web of claim 1 wherein the spaced line of weakness areclose perforations.
 5. A process of packaging utilizing an elongate webhaving front and back layers sealed together at spaced locations todefine a chain of side connected, open top bags comprising: a) feedingthe web along an elongated path of travel while supporting the web bygrasping front and back web lips; b) the feeding step includingtransporting the web into and through a load station; c) as each bag isfed into the load station opening a lead portion of the bags byspreading the lips to a loading width and thereby separating the lipsfrom each such bag by tearing separable lead lines of weakness in thefront and back layers, the lead lines extending parallel to the path oftravel with the length of each separable line being substantially onehalf the loading width in length; d) limiting the extent of lead portionopening with solid front and back web portions extending from thesupporting lips toward a bottom of the bag being opened; and, e)thereafter separating the lips from a trailing portion of the bag beingopened by tearing the face and back along further and spaced lines ofweakness.
 6. The process of claim 5 wherein the lead and further linesof weakness each have a length equal to about one half said loadingwidth whereby each such bag is opened into a substantially rectangularconfiguration.